Outcomes after unplanned admission to hospital in older people: ill-defined conditions as potential indicators of the frailty trajectory

Abstract

Objectives: To describe outcomes after unplanned hospital admission in older people and to determine whether disease trajectories in those admitted with ill-defined conditions (symptoms and signs) are distinct from other diagnostic groups and consistent with known disease trajectories.

Design: Longitudinal follow-up after a retrospective cross-sectional study of emergency admissions to general internal and geriatric medicine units in one hospital.

Setting: Acute hospital in southern England.

Participants: All people aged 65 and older with unplanned admissions to general internal and geriatric medicine inpatient units during 2002 (N = 5,312).

Measurements: Age, sex, comorbidity, presence of cognitive and mood disorders, residence, and primary diagnostic group at discharge. Outcomes were death up to 36 months from admission, any readmission, and readmission for ill-defined conditions up to 36 months after discharge.

Results: There were significant differences in death rates between the diagnostic groups, with mortality being highest in individuals with a primary diagnosis of cancer and lowest in the ill-defined conditions group. Nearly 83% of the ill-defined conditions group survived the follow-up period. Adjusted Cox proportional hazard models indicated that, when age, sex, comorbidity, residence, and cognitive and mood disorders were accounted for, the ill-defined condition group had a lower risk of death but a higher risk of subsequent readmissions for ill-defined conditions than any other group. Overall readmission risk was highest for individuals admitted for a respiratory condition but was similar in all other diagnostic groups.

Conclusion: The lower mortality risk associated with ill-defined conditions is consistent with chronic rather than acute needs, but the pattern of mortality and readmission is more consistent with the frailty than the chronic organ system failure illness trajectory, suggesting that functional support needs may be more important in this group of individuals.